In this study, we evaluated the antibacterial activity of hydrolysates from lupin protein in vitro against gram positive (Staphylococcus aureus and Bacillus subtilis) and gram negative (Pseudomonas aeruginosa and Escherichia coli) bacteria and in food system (in minced beef under refrigerated condition). Hydrolysis of lupin protein with Alcalase was monitored for 4h. Hydrolysates obtained after 1, 2, 3 and 4h had degree of hydrolysis values of 9%, 16%, 23% and 25%, respectively. The minimal inhibitory concentration (MIC) of LPH was determined against all bacterial strains. MIC value of LPH against all bacterial strains was 100 µg ml-1. The results showed that gram positive bacteria were more sensitive than gram negative bacteria. Adding LPH at different concentrations (100, 150 and 200 µg/g) to minced beef showed antibacterial activity during storage at 4°C compared to nisin (200 µg/g) as a positive control. The results of this study showed that enzymatic hydrolysis by Alcalase at pH 7.8 and 55 °C for 240 min is an easy tool to increase the antibacterial activity of lupin protein against both gram negative and gram positive bacteria and can be used as a bio-preservative in food system. Extending the technological validity of minced beef will help avoid big losses of minced beef and enhance its chances to be incorporated into many meat products while avoiding hygienic, chemical and technological deterioration.
Key words: Lupin protein; Antibacterial; Minced beef; Hydrolysis; Alcalase; Antibacterial activity.
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